how to fix Tesla Model 3 Original (2017-2023) check engine light P0420

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the vehicle's battery to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

1. Remove the upstream oxygen sensor:
   • Locate the upstream oxygen sensor near the exhaust manifold.
   • Use an oxygen sensor socket to carefully unscrew and remove the sensor.
2. Install the new upstream oxygen sensor:
   • Apply anti-seize compound to the threads of the new sensor.
   • Screw in the new sensor by hand, then tighten it to manufacturer specifications (typically 22 ft-lbs).
3. Repeat for the downstream oxygen sensor if necessary.

3. Check and Replace Catalytic Converter (if needed)

1. Inspect the catalytic converter:
   • Look for signs of physical damage or excessive carbon buildup.
   • If there are issues, proceed to replace it.
2. Remove the old catalytic converter:
   • Disconnect any heat shields, if applicable.
   • Unbolt the catalytic converter from the exhaust system using a socket set.
3. Install the new catalytic converter:
   • Position the new unit correctly and bolt it into place.
   • Ensure all gaskets are replaced and secure all connections.
4. Reconnect any heat shields and ensure everything is properly aligned.

4. Clear Codes and Reconnect Battery

• Reconnect the battery terminals.
• Use an OBD-II scanner to clear the P0420 code from the system.